Antenna switch



April 8, 1941.

F. GRASSNICK EI'AL ANTENNA SWITCH FiIed March 2l, 1939 w Si Patented Apr. 8, 1941 ANTENNA SWITCH Franz Grassnick, Fritz Kannwitz, and Willi Tiebe,

Berlin, Germany, assignors to vTelefunken Gesellschaft fr Drahtlose Telegraphie m. b. H., Berlin, Germany, a corporation of Germany Application March 21, 1939, Serial No. 263,218

. In Germany March 22, 1938 14 Claims. (C1. Z50-33) This invention is concerned with an antennaground switch comprising a protective sparkgap or arrester and antenna duct or bush of the kind used for connecting a transmitter or a receiver apparatus with a high (vertical) antenna. The problem is to connect the antenna from the inside of the transmitter house by direct or indirect drive with the ground lead, and to disconnect at the same time the transmitter from the antenna. of the antenna-ground switch, itself, is to be located outside the said sending station house, and the grounding path should be brought as rectilinear as possible because of the rules and regulations against lightning and its dangers. Moreover, the means by which the antenna lead is brought through the wall of the station house should involve the lowest possible losses. In order to safeguard against over-voltage, `there should in addition be provided a sprak-gap or arrester (coarse and ne arrester) between antenna and ground; the discharge path of the arrester should also be as straight asI feasible.

According to the invention, an antenna ground switch comprising a protective spark arrester device and antenna wall duct is So designed that the switch shaft constitutes at the same time the inner conductor of an energy feeder of co-axial or concentric design serving as the wall duct or lead-in. Preferably at the transmitter end of the lead-in, a switch contact is mounted which disconnects the transmitter from the line, while at the aerial end of the same, switch contacts or terminals are mounted in such a way that, upon closing, the antenna is connected with the transmitter, while when disconnecting or opening, the antenna is connected to earth. The duct or lead-in line Whose inner conductor forms the switch shaft is preferably so proportioned that its surge impedance is roughly equal to the surge impedance of the associated energy feeder line brought to the transmitter. In a preferable embodiment, also the means located outside the wall of the transmitter station house which consists of the ground switch and the protective sparkgap or arrester may be shielded, and the shield may change into the outer conductor of a co-axial antenna lead. By choosing such an arrangement of the parts there results an extremely practical mounting which combines low-loss lead-in of the antenna feeder lead for connection with the transmitter with an antenna-ground switch which can be driven from the interior of the station house either `directly or indirectly.

The switch operating part Y Fig. l is a cross section view of the antenna ground switch.

Fig. 2 is a diagrammatic showing of the circuit when the switch is in one position.

Fig. 2b is a diagrammatic showing of the circuit When the switch is rotated to another position.

The invention shall no-w be described more fully by the aid of an exemplified embodiment shown in Fig. l. Referring to Fig. 1, I denotes the wall of the station house in which a masonry pipe has been fitted as indicated at 2 which serves to accommodate the energy feeder line of which the outer conductor 3 by means of the casing 4 is screwed fast by flanges 5 on the pipe 2. The inner conductor 6 of the lead-in line which acts at the same time as a switch shaft is journaled in the ceramic spacers `I and 8. The inner conductor by way of a ceramic insulator 9 is united With the quadrangular end I0 on which is tted a switch wheel (not shown) or some other device adapted to actuate the switch by way of a rod system or the like. By the switch contact II the inner conductor 6 of the lead-in line is connected with the inner conductor I2 of the energy feeder or downlead I3 brought to the transmitter S. The switch II is conned within a shielding case 23 which is associated with the outer conductor 3 of the lead-in line and the outer conductor of the energy feeder line I3. All of the switch contacts that are used are of the frictional block type being pressed together by spring pressure. The whole arrangement assures gas-tight closure between the inside of the station house and the outer space. Casing 4 of the ground switch is tightly closed by the ceramic block I4 in which are embedded the antenna contact I5 and the ground terminal I6. At the antenna end of the switch shaft 6 are three switch terminals Il, two of these only being visible in the drawing. In the exemplified embodiment here shown antenna A is connected by way of the inner conductor I8 of the shielded antenna lead I9, the block contact I5 and the upper block contact I1, the switch shaft 6, the switch terminal II and the inner conductor I2 of the transmitter end energy feeder with the transmitter. The antenna contact I5 is united with the ground terminal I6 by way of the spark-gap or arrester 20 which insures a straight discharge path in the case of over-voltages from the antenna A to ground E; For insuring fine lightning protection, a rare-gas tube 2I is connected in parallel relation to the spark-gap.

The spark-gap andthe rare-gas tube or arrester,

as in the exemplified embodiment here shown, may be surrounded by a shielding shell 22 so that perfect shielding all the way from the aerial to the transmitter is insured.

Figs. 2a and 2b show again in schematic form the switch according to the invention in opened and in closed condition. The reference numerals designate the same parts as in Fig. l. Fig. 2a shows the antenna in grounded state. They transmitter in this case as will be seen is disconnected with the lead-in line. Fig. 2b shows the switch position in which the antenna is connected with the transmitter.

The invention is not confined to the exempliiied embodiment here illustrated, in fact, there are a great many other embodiments conceivable inside the scope and spirit of the invention.

What is claimed is:

1. An antenna switch comprising a metallic tube, two ceramic disc members one of which is located at each end of said tube, a rotatable metallic shaft passing through the center of said disc members, two metallic casings one of which is located at each end of said tube, and switch contact means within each of said casings for selectively connecting an antenna to a radio transmitter or ground when said shaft is rotated.

2. An antenna switch for a concentric energy feed line comprising a metallic tube, a rotatable switch shaft, said tube and said shaft serving as outer and inner conductors respectively for said feed line, two fiuid-tight casings each one of which is located at an end of said tube, a lightning arrester within one of said casings, Contact means within said casings for selectively connecting an antenna to a radio transmitter or ground when said shaft is rotated.

3. An antenna switch for a concentric energy feed line comprising a metallic tube, a rotatable switch shaft, said tube and said shaft serving as outer and inner conductors respectively for said feed line, two fluid-tight casings each one of which is located at an end of said tube, contact means within said casings for selectively connecting an antenna to a radio transmitter or ground when said shaft is rotated.

4. An antenna switch for a concentric energy feed line comprising a metallic tube, a rotatable switch shaft, said tube and said shaft serving as outer and inner conductors respectively for said feed line, two fluid-tight casings each one of which is located at an end of said tube, a lightning arrester and a spark gap within one of said casings, contact means within said casings for selectively connecting an antenna to a radio transmitter or ground when said shaft is rotated.

5. An antenna switch for a concentric energy feed line comprising a metallic tube, a rotatable switch shaft, said tube and said shaft serving as outer and inner conductors respectively for said feed line, two fluid-tight casings each one of which is located at an end of said tube, a lightning arrester and a spark gap within one of said casings, said lightning arrester and said spark gap connected in parallel with each other, and contact means within said casing for selectively connecting an antenna to a radio transmitter or ground when said shaft is rotated.

6. An antenna switch for a concentric energy feed line comprising a metallic tube, a rotatable switch shaft, said tube and said shaft serving as outer and inner conductors respectively for said feed line and having substantially constant surge impedance, two fluid-tight casings each one of which is located at an end of said tube, contact means within said casings for selectively connecting an antenna to a radio transmitter or ground when said shaft is rotated.

'7. An antenna switch 'comprising a metallic tube for passing through the wall of a building, two ceramic disc members one of which is located at each end of said tube, a rotatable metallic shaft passing through the center of said disc members, two metallic casings one of which is located at each end of said tube, operating means for rotating said shaft within the building, a lightning arrester within the casings located outside the building, and switch contact means within each of said casings for selectively connecting an antenna to a radio transmitter or ground when said shaft is rotated.

8. An antenna switch comprising a metallic tube, two ceramic disc members one of which is located at each end of said tube, a rotatable metallic shaft passing through the center of said disc members, two metallic casings one of which is located at each end of said tube, an insulating member secured to the inside of each one of said casings, and switch contact means mounted on said insulating members for selectively connecting an antenna to a radio transmitter or ground when said shaft is rotated.

9. An antenna switch comprising a metallic tube, two ceramic disc members one of which is located at each end of said tube, a rotatable metallic shaft passing through the center of said disc members, two metallic casings one of which is located at each end of said tube, an insulating member secured to the inside of each one of said casings, a transmitter lead passing through one of said casings, an antenna lead and a ground terminal passing through another one of said casings, and switch contact means mounted on each one of said insulating members for selectively connecting the antenna lead to the transmitter lead or the ground terminal when said shaft is rotated.

l0. An antenna switch comprising a metallic tube, two ceramic disc members one of which is located at each end of said tube, a rotatable metallic shaft passing through the center of said disc members, two metallic casings one of which is located at each end of said tube, two contact arms each one of which is located at opposite ends of said shaft, and switch contact means within each of .said casings for selectively connecting an antenna to a radio transmitter or ground when said shaft is rotated.

1l. An antenna switch for a concentric energy feed line-comprising a metallic tube, a rotatable metallic shaft, said tube and shaft serving as outer and inner conductors respectively for said Afeed line, said tube and rotatable metallic shaft being so proportioned that the surge impedance of the concentric conductor thus formed is substantially equal to the energy feed line, two huid-tight casings each one of which is located at an end of said tube, and contact means within said lcasings for selectively connecting an antenna to a rdio transmitter or ground when said shaft is rotated.

l2. An antenna switch comprising a metallic tube for passing through the wall of a building, two ceramic disc members one of which is located at each end of said tube, a rotatable metallic shaft passing through the center of said disc members, two metallic casings one of which is located at each end of said tube, operating means for rotating said shaft within the building, and a lightning arrester within the casing which is located outside the building, switch contact means within each of said casings for selectively connecting an antenna to a radio transmitter or ground when said shaft is rotated, and an insulating member interposed between said rotatable shaft and said operating means.

13. The combination of an antenna ground switch, a radio transmitter, an antenna, a rst feed line having an inner and an outer conductor for connecting said transmitter to said switch, a second feed line having an inner and an outer conductor for connecting said switch to said antenna, said switch comprising a metallic tube for passing through the wall of a building, two insulating disc members one of which is located at each end of said tube, a rotatable metallic shaft passing through the center of said disc members,

two metallic casings one of which is located at 20 each end of said tube and electrically connected thereto and to the outer conductors of both feed lines, and switch contact means within each of said casings and cooperating with said rotatable shaft for` selectively connecting the inner conductor of said feed lines from said antenna to said radio transmitter or ground when said shaft is rotated.

14. The combination of an antenna ground switch, a radio transmitter, an antenna, a rst feed line having an inner and an outer conductor for connecting said transmitter to said switch, a second feed line having an inner and an outer conductor for connecting said switch to said antenna, said switch comprising a metallic tube for passing through the wall of a building, two insulating disc members one of which is located at each end of said tube, a rotatable metallic shaft passing through the center of said disc members, two metallic casings one of which is located at each end of said tube and electrically connected thereto and to the outer conductor of both feed lines, a Contact switch arm located at each end of said shaft, and switch contact means within each of said casings and cooperating with said rotatable contact switch arms foi` selectively connecting the inner conductors of said feed lines from said antenna to said radio transmitter or ground when said shaft is rotated.

FRANZ GRASSNICK. WILLI TIEBE. FRITZ KANNWITZ. 

